Electrical switching apparatus



June 20, 1933.

w. M.- SCOTT ELEc'rRIcAL SWITCHING APPARATUS 4 Sheets-Sheet 1 FiledApril 12, 1929 INVENTORFI'G w. BY @ng 16.

} ATTO NEY FIG. 3 22 25 June 20, 1933.

W. M. SCOTT ELECTRICAL SWITCHING APPARATUS Filed April 12, 1929' 4Sheets-Sheet 2 FIG. I?

o INVENTOR F76. 2 l v M 1 ATTORNEY June 20, 1933. w. M. SCOTT 1,914,532

ELECTRICAL SWITCHING APPARATUS Filed Apri1 12, 1929 4 Sheets-Sheet s Lsilllll W: r l '1--6 INVENTOR i I ATTORNEY June 20, 1933. M, SCQTT1,914,582

ELECTRICAL SWITCHING APPARATUS Filed April 12, 1929 4 Sheets-Sheet 4 1077 INVENTOR no 7 9i 2 BY W24 mm 152. ATTORNEY Patented June 20, 1933UNITED STATES PATENT OFFICE WILLIAM m. sooner, or 'rrmnrrram TOWNSHIP,CHESTER COUNTY, PENNSYLVANIA,

ASSIGNOR TO LT-E CIRCUIT BREAKER COMPANY, OF PHILADELPHIA, PENNSYL-VANIA, A CORPORATION OF NEW JERSEY ELECTRICAL SWITCHING APPARATUSApplication filed April 12,

of the contact structure to closed positionupon movement of the switchoperating structure.

My invention further resides in a system of dual protection fora circuitwherein anautomatic circuit breaker connected in said circuit is trippedopen in response to either a predetermined instantaneous value ofoverload or a predetermined and continued overload of lower magnitude;and more particularly said tripping means comprises two independentlyactuated armatures selectively coacting with a common latch actuator ofthe circuit breaker, one of said armatures have relatively small massand actuated upon occurrence of a predetermined instantaneous value ofoverload, and the other armature having relatively greater mass andoperatively connected to a start-delay or sucker element, wherebyactuation thereof to. trip open the circuit breaker is effected onlyupon occurrence of predetermined and prolonged overload. .My inventionfurther resides in means for effecting a common adjustment of a pair oflarmatm'es, a separate adjustment .of one armature affecting thetripping point of 'another, whereby simultaneous adjustment of saidarmatures varies the tripping range of one of them within predeterminedlimits while maintaining the tripping point of the other substantiallyconstant; and more particularly the pivotal mountings for said armaturesare disposed transversely of,'or at an appreciable angle to, anotherportion of the. magnetic circuit whereby the magnetic im.-

pulses, as in an alternating current system,

acting upon an armature at its mounting,

do not di'rectly' oppose the force of gravity,

1929. Serial No. 354,480.

thereby substantially obviating chattering I or vibration'of saidarmature. I My invention further resides 1n a combination of a switch orautomatic circuit breaker and structure movable to either one of aplurality of positions, in one of. which it permits free or normaloperation of the switch or circuit breaker, and in another of which itprevents actuation or operation of the switch or circuit breaker; andmore particularly prevents reclosure of the switch or circuit breaker;and more particularly there is provided means for latching or holding aswitch or.circuit breaker housing to its supporting structure or base,and so related to the aforesaid combination that a single locking means,such as a padlock or equlvalent, may simultaneously lock it and theaforesaid movable. structure, the latter in either of its positionsaforesaid.

My invention further resides in apparatus of the character hereinafterdescribed and claimed.

For an understanding of my invention,

reference is had to the accompanying draw ings, in which Fig. 1 is aside elevational view of electrical switching apparatus.

Fig. la; is a side view of core structure.

Fig. 1b is a front view of the structure illustrated in Fig. 1a), withcoacting armatures. I

Fig. 2 is a front elevational view, partly broken away, of the apparatusillustrated in Fig.- 1. I

Figs. 3, 4, and 5 are detailed projected views of structure illustratedin Fig. 1.

6 is a top plan View, partly in section, of the magnetic blow-outstructure.

Fig. 7 isv a front elevational view of the structure illustrated in Fig.6.-

Fig. 8 is a front elevational view of a pair of magnetic blow-out coils.

Fig. 9 is a side elevational view of the coils illustrated in Fig. 8.

Fig. 10 is a detailed view of the switch operating structure in theposition illustrated in Fig. 1.

Figs. 12, 13, and 14 are detailed views in projection of a switch armsupporting member.

Figs. 15 and 16 are detailed views in projection illustrating anarmature.

F igs.'17 and 18 are detailed views in projection illustrating a similartype of armature.

Figs. 19 and 20 are detailed views in projection of structure includedin Fig. 1.

Fig. 21 is a side elevational view, partly in section, of switch housingstructure.

Fig. 22 is a front elevational view, partly broken away, of Fig. 21.

Fig. 23 is a lower plan view of Fig. 21.

Fig. 24 is a view showing the parts in Fig. 22 in another position.

Referring to Figs. 1 and 2, a base or panel 1 of suitable insulatingmaterial, is provided with barriers 1a extending transversely theretoand has mounted thereon electrical switching apparatus comprising astationary contact 2 suitably secured to the base, as by a conductingstud 3 which comprises a lead conductor of the circuit to be protected,and a movable contact 4 mounted upon a transversely extending bar orsupport 5, and electrically connected by a flexible conducting strip 6to a terminal 7 on the bracket 8 secured to base 1. Terminal 7 isconnected to one end of anoverload coil 9 whose other end is connectedto the con-v ducting stud 10 comprising the other lead from the circuit'to be protected.

Cooperating with movable contact 4, and mounted also upon the switch armsupport 5 is an auxiliary or arcing contact 11 carried on the end of aresilient conducting arm 12. In the closed position of the switch,contact 11 is in engagement with a contact 13' suitably secured to thebase, as by screw 13a, which is positioned and spaced with respect tocontact 2by a raised portion or boss 13b forming a part of the base.Means for extinguishing the are between contacts 11 and 13, referringmore particularly to Figs. 8 and 9, comprises a pair of blow-out coils14 and 15 arranged on each side of the contacts in the usual manner, andhaving theirinner ends connected to each other by'a conducting strip orbridge 16, and their outer ends connected together by 'a conductingstrip 17 having a rectangular opening 18 therein for 'a purposehereinafter described. Conducting strip 16 is suitably secured to thebase by contact 13 and is in electrical contact therewith. ,Theconducting strip 17 is likewise clamped to the base by contact 2, theextension of which passes through aperture 18, thereby connecting ,coils14 and 15 in parallel between contacts 2 and 13.

Insulating enclosing structure for the blow-out coils, referring moreparticularly to Figs. 3 to 7 inclusive, comprises partienclosing theblow-out coils. Except tions or walls 19 preferably integrally mountedto the base or panel 1 as by moulding, and of substantially the samematerial, and cover members 20 of arc-resisting material detachablysecured with respect to the base and partitions. As viewed in Figs. 6and 7, an individual pair of blow-out coils are disposed adjacent theopposing faces of two partitions or walls, and are suitably housed bythe cup-like covers 20 which form with partitions 19 receptacles forcompletely or the end walls, the members 19 form common wall structurefor a pair of unrelated coils. Each partition or wall 19, as previouslymentioned, is preferably moulded to base 1, forming an integral parttherewith, and is of insulating material. The cover members are sodesigned that they are readily removable to afford access to the coils.To this end, the cover members 20 are each provided with offset portions21, Figs. 4 and 5, adapted to abut each other when the covers are inposition to shield and protect an appropriate portion of base 1 notshielded by the contact 13, and to furthermore space the cover membersfrom each other to provide suitable clearance for the movable contactelement I between the same. The interior of each cover member 20 isprovided with a shoulder 22 extending along three sides of the same forengaging the corresponding edges of a partition 19 to relativelyposition the same. The edges of the cover abutting base 1 seat within acorrespondingly shaped depression 20a in the base 1 and have a pair ofnotches 23 and 24 therein for receiving the bridging conductors 16 and.17 respectively of the blow-out coils. The front side of the coverpartially overlying the outer ed of the partition is provided with asemi-circular notch 25 and a longitudinally extending recess 26 forreceiving a holding screw 27 and a clamp 28. Screw 27 is secured, as byan insert 27a, to the front edge of partition. 19 and serves to clampthe front edge of cover 20 to the partition. As viewed in Fig. 6, two ofthe partitions 19, when three pairs of blow-out coils are employed, havea cover member mountdo'n each side thereof and clamped thereto by commonclamping structure 27 and 28. Accordingly,'quick and easy access to theblow-out coils may be accomplished by on the basal. Referring moreparticularly to Figs. 10 and 11, the switch operating structurecomprises a pair of toggle links 32 and 33 pivotally connected to eachother at 34 and having their opposite ends pivotally connected at 35 and36 to members 29 and 37 respectively. Member 37.is pivotally mounted at38 to the fixed support or bracket 31 and carries at its outer end alatch 39 pivoted at 40, having a notched portion 41 for engaging theextension or locking detent 42 of the toggle link 33. A latch member 43pivotally carried by member 29 at 35 comprises a notched portion orrecess 44 at the lower edge of its free end, and a shoulder 45 abuttingflange 29a of member 29 to prevent further rotation in a clockwisedirection. As viewed in Fig. 10, the'switch operating structure is incircuit-closing position, and latch 43 is maintained out of engagementwith the other elements of the structure by shoulder 45. Toggle 32-33isshown in extended position although slightly undertravelled, and ismaintained in such position by latch '39 carried bythe-main operatinglever 37', which forms with link 32 a second toggle comprising pivots35, 34 and 38. Link 33 and arm 37 being latched to each other, the twomembers operate as a unit to form the second toggle which isover-travelled to a small extent, pivot 34 being slightly above thecenter line of pivots 35 and 38, and therefore remains in this positionuntil tripped in a manner'hereinafter described. Latch 39 comprises atail-like extension 39a adapted to be engaged by a tripping bar 46 torotate the latch in a clockwise direction. 'Upon tripping movment ofmember46 to move latch 39 clockwise, the shoulder 41 of latch 39 movesout of engagement with detent 42 of the toggle link 3.3,releasing link33 from the operating arm 37 and permitting the undertravelled toggle32-33 to collapse, thereby causingimmediate collapse of the operatingstructure to the position shown in Fig. 11,

which is representative of the open position of the switch. Member 29 isbiased by a spring 47 in a clockwise direction, one end of the-springbeing secured to an extension 48 of member 29 and the other end to a lu49' mounted upon the operating arm 37 (Figs. 1 and 2). As the toggleoperating structure moves to the open circuit position illustrated'inFig. 11 under the influence of gravity and spring 47, latch 43 will movewith member 29 in a clockwise direction and will engage by its cammingedge 43a pivot pin 36interconnectingthe link 33 an'd the operating arm37. Accordingly, latch '43 will ride upon pivot pin 36 until, notch 44permits the latch to drop into engagement with the same to lock member29 in the position shown in Figill. Counterclockwise rebound of member29 is accordingly checked while latch 43 is in engagement with pin 36,

due to the fact that the operating member 37, by which pivot pin 36 iscarried, is'

tion is limited by the stop means previously referred to, pin 36willmove out of notch 44. Accordingly, after link 33 and arm 37- havebeen latched together the operating arm 37 is moved in clockwisedirection to extend the toggle structure to circuit-closin position asillustrated in Fig. 10. It will be noted that member 29, on which themovable contacts of the switch are mounted as a unit, is caught and heldin substantially its fully opened circuit position by latch 43, whichprevents the movable contact structure from rebounding towards thestationary contacts, and from vibrating violently as in the case wherethe switching inechanism is caused to open with more than the usualforce: Rebounding of the movable contacts any movement is objectionablein practice, and if the rebound should cause the movable contacts totouch their cooperating stationary contacts, freezing of the sametogether would in all probability result.

The supporting bar 5 for the movable contacts, referring to Figs. 12,13, and 14, comprises an insulating bar -having recesses 50 in one sidethereof for receiving conducting strips 6-and the contact supportingstrips 4 andv 12. Inserts 51 extend through memor, substantial part oftheir total 7 cos ber 5for receiving securing means, as screws,

comprises a recess 55 within which is mounted an arm 56 carrying anindicatingdevice 57, whose position indicates the circuit position ofthe circuit breaker.

Electromagnetic means for automatically I tripping the electromagnethaving a coil 9,1 hollow core 58 and pole pieces-59 and 60'at o positeends of the core.

circuit breaker comprise an The front poe piece 60 is clamped, togetherwith a trans;

versely extending coil support or bar 61,

hereinafter described, in posltion by suitable means as a bolt 62extending through core 58 and clamped to base 1.

Core 58, referring to Figs. 1a and 1?), comprises a hollow tubularmember to which are secured pole piece 59 at one end and pole piece 60at the other end. Pole piece 60 and core 58 are slotted, 01 divided, asat 5841, so that the magnetic field from the lower tip of pole piece 60will vary according to the proportion in which the pole piece isdivided. Slot 58a, though preferably extending partly back through thecore, may extend back any desired distance up to the entire length ofthe core. As will be noted in Fig. lb, slot 58a. divides the loweroutwardly turned portion of the pole piece 60 into parts 60a and 60?),part 60a; having appreciably less cross section than part 601).Accordingly, for a given amount of flux 1produced by the overload coil9, and negecting saturation effects, the strength of the magnetic fieldspassing through the divided portions of pole piece 60 variesapproximately as their respective cross sections. In Fig. 1b therelative positions of armatures 63 and 64 with respect to each other andthe pole piece, are somewhat exaggerated and do not necessarilyrepresent the actual positioning of said elements in practice.

Member 61, Figs. 19 and 20, has recesses 83 for receiving the front polepieces of the individual trip magnets, and notches 84 within which theedges of barriers 1a are fitted. Apertures 85 for receiving the latchactuating pins 81' for engaging tripping bar 46 extend verticallythrough bar 61 and comprise three individual pairs corresponding to thethree pairs of armatures hereinafter described. The apertures'86 receivebolts 62 for clamping the bar in position. The lower edge of bar 61seats upon offset portions of barriers 1a, Fig. 1.

A pair of armatures 63 and 64 are pivoted independently of each otherupon a supporting pin 65 carried by lugs 66 forming a part of bracket 31and of non-ma netic material, such as brass for examp e. Lugs 66 extendtransversely of or at an appreciable angle to the lower portion of polepiece 59 for a purpose hereinafter described. Armature 63, Figs. 15 and16, comprises a portion 67 of mag etic material having a downwardlyturned lug 68 at its pivoted end. The armature is suitably weighted by amember 69 of non-magnetic material, such as brass for example, thenon-magnetic member being turned upwardly at its outer end to providegreater mass for a given over-all length of'the armature. An aperture 70for receiving a pivot pin 71 provides means for connecting armat-ure 63to a sucker apparatus S comprising a time-delay feature. The pivotalbearing of armature 63' comprises a strip the pole ,gage and pushupwardl of non-magnetic material 72 secured to the under side of thearmature and having a bent-over portion 73 and a struck-out por tion ortongue 74 within which pivot pin 65 is disposed. Member 72 alsocomprises transversely extending portions 75 for properly spacingarmature 63 with respect 'to the other armature 64. Armature 64 isindependently of armature 63, as 1n response to an instantaneous impulseof sufiicient magnitude. Armature 64 has appreciably less magneticsusceptibility than armature 63, its iron or magnetizable member 76being considerably smaller than the corresponding member 67 of armature63, and in its inactive position in the circuit breaker, armature 64 ismore remote from pole piece 60 than is armature 63. By suitablevariations of these factors and of the 1 total weights of the respzctivearmatures, any desired relation may secured between their respectivetripping points.

By magnetic susceptibllity'is meant the responsiveness to magneticattraction, and in the present instance it is dependent upon a number offactors.- These factors include the cross section of the magnetizableportion of an armature as compared with the total weight of the movingsystem; the relative areas of the armatures exposed to the pole of themagnet; the respective distance of each armature from the pole of themagnet in its normally unattracted position;

and the relation of the distance of one armature to that of the otherwith respect to the pole of the magnet.

Referring to Figs. 1 and 2, the armatures 63 and 64 are disposed intheir unattracted positions at varying distances from pole pieee 60 andin coaeting relation with the I divided pole portions so that the fieldof rtion 60a acts upon armature 64, and the old ofportion 60b acts uponlarger armature 63. ccordingly, the armatures 63 and 64 are individuallyacted upon by magnetic fields whose strength in general depends upontheratio' in which-the pole piece 60 is divided.

Each of the armatures is adapted to ena corresponding latch-actuatingpin 81 w ose upper rtion 82 may freely engage the latch-tripping bar i46. Accordingly, when either armature 63 or 64 is urge y the field ofcoil 9 in 'a no I ,to mount the armatures below the extension of thepole piece, and to utilize a spring or equivalent to prevent chatteringor vibration of the armature when used in an alternating current system.This chattering is due to the fact that the-magnetic forces tending toattract the armature upwardly act in direct opposition to the force ofgravity, which is constant. Accordingly, when the magnetic forcefluctuates or ulsates, chattering of the armature will result when thisconstruction is used unless special means are' used to prevent it. Inthe construction shown in Fig. 1, the magnetic forces at the pivot endsof the armatures act to move them horizontally, and not vertically, andso act substantially at right angles to the force of gravity.Accordingly, the pulsating force tending to produce chattering of thearmature is eithermaterially minimized or I reduced to zero without theuse of additional means to this end. There is no appreciable chatteringat the free ends of the armatures due to the weight of the armatures andtheir spacing from the pole piece 60. The armatures do not pull up untilcurrent fiow ing in the coil 9 reaches the operating values for whichthe armaturesare respectively adjusted, at which time one of thearmatures, depending upon the particular condition existing, will pullup (after a suitable time delay in the case of'armature 67) and'trip thecircuit breaker.

The armatures 63 and 64 are so propor tioned and placed with respect'tothe pole piece 60 that armature 63 will react to a much smaller currentthan will armature 64;.

due, however, to the action of the time limit feature associated withthe armature 63 its response to such current requires that it besustained for'an appreciable: period oftime.

In the caseof unduly heavy current flow, armature 64 responds instantlyto open the circuit breaker. Accordingly there is provided a dual systemof protection wherein the circuit to be protected is opened instantlyupon occurrence of a. very heavy overload or upon the occurrence of amore moderate overload unduly long sustained, since relatively smalltransient overloads are not sufiiciently dangerous to apparatus such asmotors to warrant the opening of the circuit and consequent interruptionof service.

Referring to Figs 21 to 24 inclusive, there is shown means for housingswitching a paratus and for concurrently locking t e housing andswitching apparatus in prede termined relations. The base or panelmembar 1 has mounted on the rear side thereof a housing 90, within whichare disposed the terminal connections (not shown) for the switchingapparatus and the usual leads emerging by way of conduit 91. A cover orswitch housing structure 92 is pivotally mounted at 93 upon the rearhousing 90,- and is pivotally movable with respect to base 1, which alsois pivotally movable with respect to housing 90. Upon the front face 94of housing 92 is mounted an o erating handle 95 which extends throughthe front wall of the housing within bearing- 95a and terminates in aswitch-actuating member 96, comprising jaw-like portions 97 and 98 (Fig.22). An aperture 57 a in wall 94 permits inspection of indicator 57. Theoperating handle 95 is normally biased to the position shown in Fig. 22by a spring 99 having one end connected 'to a lug 100 on the member 96,and the other end to an an chored member 101 secured to the bottom wallof housing 92. A locking arm 102 pivoted to wall 94 at 103 comprises, anextension 104 terminating in a recessed portion 105, and comprising atits opposite end an enlarged portion 106 provided with apertures 107 and108 for a purpose hereinafter described. Arm 102 is normally biased by aspring 109, also secured to anchored member 101, to the position shownin Fig. 22.

4 Referring to Fig. 23, the lower side of housing 92 is provided with alatch 110 pivotally mounted to the housing at 111 and comprising atransversely extending flange 112 for facilitating operation thereof.One end of latch 110 is provided with a notched recess 113 adapted toreceive a pin or lug 114 carried by the overlying portion of a lug 115,which is secured to housing 90. Accordingly, when the parts are in theposition shown in Fig. 23, housing 92 is rigidly secure withrespect tohousing 90. The opposite end of latch 110- is provided with a downwardlyturnedportion 116 provided with an aperture 117, and adapted to registerwhen in the position shown in Fig. 23

with an aperture 118 in a lu'g 119 secured to so loc ing a roller 37a,pivotally mounted at 37 b to arm 37.

The operation of the apparatus is as follows Assuming the switchingapparatus to be in the open position, and the switch locking members tobe in the position shown in Fi 22, handle 95 is first rotated inclockwise direction, whereupon jaw portion 98 engages roller 37a. tolift the same and to rotate the operating arm 37 in a counterclockwisedirection. Such movement of the operating arm eflects release of latch43 tending to restrain the contacts in open position, and upon ,furthermovement causes latch 39 to engage detent 42 of the undertravelledtoggle structure in the manner previously described. Handle 95 isaccordingly rotated in the opposite or counterclockwise direction,

whereupon jaw portion 97 engages roller 37m to rotate the operating arm37 in a clockwise direction to extend the to gle'structure tocircuit-closing position. pon completion of the circuit-closingmovement, the handle is released and assumes the position shown in Fig.22 due to the influence of s ring 99. It will be noted that during theabove described operation, lever 102 in its normally biased positiondoes not interfere with the movement of the actuating member 96, andaccordingly leve'r 102, together with latch 110, may be locked withrespect to the stationary lug 119 by passing a padlock throu hapertures118, 108 and 117. When fled, the switching apparatus is lockedwithin housings 90 and 92,'but is free to be moved to open or closedpositions. If now it is desired to lock the switchin apparatus 7 in itsopen position, arm 95 is rst rotated in a clockwise direction so thatpin 96a on member 96 will be free to clear the upper end of extension104 to register with notch 105. However, such required movement bringsthe lower jaw portion 98 into contact with roller 37 a to trip open theswitch, thereby insuring that the switch is in open position before thelocking operation is completed. The padlock or equivalent having beenremoved from apertures 108, etc., the extension 106 of lever 102 ispushed into the position shown in Fig. 24, wherein aperture 118 of thelocking lug is in re istry with aperture 107 of the lever. he membersare locked in this position, after which handle 95 is released,permitting in 96a to seat within notch 105 of the lockmg leverto'prevent further movement of member 96 in a counterclockwisedirection. Since it is essential that the main operating arm 37 berotated first in one direction, and then in the other direction tocomplete closure of the switch, it will be apparent that the switch islocked in open position as long as the members 102 and 96 are in thepositions shown in Fig. 24. Upon removal of the padlock from apertures107, etc., spring 109 moves lever 102 to cam the pin 96a out of notch105, whereupon member 96, under the influence of its spring, assumes itsnormal position.

In the opening movement of the circuit breaker, the main movable contactmember 4 is first withdrawn from the fixed contact 2; While for theinstant, movable contact 11 maintains its engagement with fixed contact13, thus bringing the blow-out coils into series with the'main circuitand thereby rendering them effective to rupture the arc drawn in thespace between them incident upon the further opening of the switch andconsequent withdrawal of contact 11 from engagement with contact 13.

In order to prevent arcing at the main contacts of the circuit breaker,it is essential that the impedance of the blow-out coils shall be aminimum consistent with the desired magnetic efi'ect. High blow-outefiiciency is attained by disposing the two coils on .o posite sides ofthe arcing chamber, the etiiactiveness thus secured being such that ironmay be altogether omitted from the magnetic circuit and coils ofrelatively few turns are found to suflice. The cover members 20 whichshield the blow-out coils, the partition members 19, and'the base areaabove the contact 13, are of material having high arc-resistingcharacteristics; accordingly, base 1 and partitions 19, beingeffectively shielded from arcing, the material from whichthese aremoulded may be selected with reference to itsinsulating qualities ratherthan for its ability to resist arcmg.

With the circuit breaker in the closed pos'ition, armatures 63 and 64,upon the occurrence of predetermined overload conditions in the circuitto be protected, selectively actuate the latch trip bar 46 to cause thecircuit breaker to open. For example: If an overload of 200 amperes ormore is deemed excessive even though occurring only for an instant,armature 64 may be so adjusted that it will immediately open the circuitbreaker when this or heavier overload occurs. Armature 63, however, isnot actuated' by this high instantaneous current since the suckers ofthe time limit device does not release its hold immediately but only inresponse to a prolonged force. Accordingly, in the 'event of purelytransient overloads of'less than 200 amperes, neither armature 63 nor 64will respond to trip the circuit breaker. In general, the desiredinstantaneous tri out current of a given circuit breaker is xed at abouteight times the rated capacity of the circuit breaker, while on theother hand, the point of trip-out on sustained smaller current must besubject to a considerable range of adjustment. This adjustment isobtained by movement of armature 63 toward or away from pole piece 60,this movement bein effected by corresponding movement of t e time limitcontaining case S along the stirrup 130 to which it may be secured inthe desired position by means of the screw 131, the correspondingtripping points being indicated by a suitable calibration scale on thefront of the time limit case considerably more re mote from the pivot 65than is the point 71 which supports the armature 63 with respect to thiscase. B a proper determination of the relative distances of therespective points of support 71 and 132 from the pivot pin 65, thetripping point of armature 64 is maintained practically constantthroughout the entire range of adjustment of itself and armature 63.

Upon the positions with respect to each other of arm-atures 63 and 64,because both are "magnetically in arallel in the same magnetic field,depen s the relative magnitudes of the fluxes through them; that is tosay, each armature effects diversion of flux from the other, and theamount of diversion from armature 63, for examfple, depends upon therelative position 0 armature 64. In addition to the fact hereinbeforestated that the position of the armature 63 with respect to armature 64affects the trip ing point of the latter, it is also inherent y truethat the position of the armature 64 with respect to the armature 63,determines the diversion of flux from the armature 63, and determinesthe extent of delay effected by the retarding device S. The amount ofdiversion by one armature upon the other may be affected by theirhereinbefore mentioned relative magnetic sus ceptibilities, sizes, andrelative weight, and by their positions with respect to the pole pieces.2

What I claim is: 1\ The combination with automatic switching apparatuscomprising a movable contact member, and a main operating member forsaid coiitact member, of means carried-byone of said members andcatching the other for restraining said movable contact membersubstantially upon completion.

of its movement to open position to prevent re-bounding of'said movablecontact member.

2. The

combination with automatic switching apparatus comprising a movablecontact member, and a main operating member for said contact member, oflatching means coacting with said contact member and operating memberengaging with and 'restrainin said movable contact member substantia lyupon completion of its movement to open position to prevent re-bound--ing of said movable contact member, said latching means adapted to bereleased upon subsequent movement of the operating member to effectclosing movement of said contact member.

3. The combination with automatic switching apparatus of the nonclosabletype comprising a movablecontact member, a main operating lever, andmeans detachably connecting said contact member to said lever, of meansfor catching and restraining said movable contact member in openposition comprising a latch member car ried by said contact member andadapted to engage a portion of said operating lever as the movablecontact member reaches its fully open position.

4. The combination with automatic switching apparatus of thenon-closable type comprising a movable contact member, a main operatinglever, means detachably connecting said contact member to said lever,and tripping means for releasing said detachablex connection to permit.opening movement of? said contact member, of means for catching andrestraining said mov'able contact member in open position comprising alatch member carried by said contact member and adapted to engage aportion of said operating lever as the movable contact member reachesits fully open position, said latching member released from theoperating lever upon movement of the same to re-establish operativeconnection with said movable contact. member prior to closing movementof 'said contact member.

5. The combination with automatic switching apparatus of thenon-closable type comprising a movable contact member, a main operatinglever, means detachably connecting said contact member to said lever,and tripping means for releasing said detachable connection to permitopening movement of said contact member, of means engaging with andrestraining said movable contact member in open position upon trippingof the switch, said means adapted to be moved out of restrainingengagement upon movement of the operating lever t-o re-establish theconnection between the same and said contact member prior to move- ,mentof the contact member to closed po sition.

6,.The combination .with automatic switching apparatus of thenon-closable type comprising-a movable contact member, a main operatinglever, an undertravelled toggle structure connected to said confrom saidlatching engagement upon movement of the operating lever to reestablishconnection wit said toggle structure.

7. The combination with automatic switching apparatus of thenon-closable type comprising a movable contact member, a

main operating lever, an undertravelled toggle structure connected tosaid contact member and said arm at a point removed from its pivot,means detachably connecting an element of said structure to saidoperating lever to form an overtravelled toggle, and tripping means forbreaking said connection to permit collapse of the under travelled togle structure and openin of the switch, 0% means for catching anrestraining said movable contact member in open position comprising alatch member carrie by that end. of the undertravelled toggle connectedto the movable contact member and adapted to engage the oppbsite end ofsaid toggle connected to the operating lever, said contact member beingreleased from said latching engagement upon movementof the operatinglever to reestablish connection with said toggle structure.

8. An electromagnet comprising magnetizable core structure, a pivotedarmature completing a magnetic circuit with said core structure when insubstantially horizontal position, and means mounting said armature tosaid structure whereby the magnetic forces acting on the pivot of saidarmature are at substantially right angles to the force of gravityacting thereon and tend to efiect movement in a substantially horizontalplane.

9. An electromagnet comprising magnetizable core structure, a pivotedarmature completing a magnetic circuit with said structure when insubstantially horizontal position, and means mounting said armature tosaid structure whereby the magnetic forces acting on the pivot of saidarmature are at a relatively reat angle to the force of gravity acting tereon.

10. An electromagnet comprising magnetizable core structure having adepending pole piece, a pivoted armature normally positionedsolelybygravity completing a mag-' netic circuit with said structurewhen in substantially horizontal position, and means mountingsaidarmature adjacent and substantially laterally of said pole piece topreclude chattering of the armature.

11. An electromagnet comprisin magnetizable core structure having aepending pole piece, a pivoted armature completing a magnetic circuitwith said structure when in substantially horizontal position, andnonmagnetic means upon which'said armature is mounted disposedsubstantially laterally of and at a relatively great angle to the lowerextension of said pole piece whereby the magnetic forces tending toattract said armature towards said pole piece act at an appreciableangle'to the force of gravity.

12. A magnetic structure comprising a core, pole pieces, an energizingcoil therefor, a plurality of armatures coacting selectively therewith,and adjusting means common to said armatures unequally efiectivetherefeet said selectivity in a predetermined relation upon movementthereof.

13. The combination with an automatic circuit breaker comprising movablecontact structure, means for retaining said structure in normal.position, and tripping means therefor, of a magnetic structurecomprising a core, pole ieces, an energizing coil therefor, a plur.v ityof armatures coacting selectively therewith to actuate said trippinmeans, and adjusting means common to sai armature's unequally effectivethereupon said adjusting means adapted to affect said selectivity in apredetermined relation upon movement thereof.

14. The combination with an automatic circuit breaker comprising movablecontact structure, means for retaining said structure in normalposition, and tripping means therefor, of magnetic structure comprisingan electromagnet, a plurality of armatures coacting selectivelytherewith to actuate said tripping means, and means common to saidarmatures for adjusting them simultaneously and differentially withrespect to said electromagnet.

15. The combination with an automatic circuit breaker comprising movablecontact structure, means for retaining said structure in normalposition, and tripping means therefor, of magnetic structure comprisingan electromagnet, a plurality of armatures coacting selectivel therewithto actuate said tripping means, the magnetic susce tibility of saidarmatures being affected y their relative positioning with respect toeach other and said electromagnet, and means common to said armaturesfor adjusting them simultaneously and difi'erentiall with respect tosaid electromagnet where y the magnetic susceptibility of one of saidarmatures with res ct to said electromagnet is maintained an tiallyconstant.

netizable core member, a pole piece for said,

, core member divided into components for dividing the magnetic field,and a plurality of armatures operatively related respectively to saidpole piece components.

' 17. An lectromagnet comprising a divided magnetizable core member, apole piece divided into components operatively related respectively tothe components of ,said core member for dividing the magnetic field, anda plurality of armatures operatively related respectively to said polepiece components.

18. An electromagnet comprising a magnetizable core member, a pole piececoacting with said core member divided into a plurality of componentsfor dividing the mag netic field, and a plurality of armatures coactingrespectively with the com onents of said pole piece and disposed at dierent distances therefrom.

19. An electromagnet comprising a magnetizable core member, a pole piececoacting with said core member and divided into components of differentwidths for dividing the ma etic field, and a plurality of armatures 0different widths coacting respectively with said pole piece components.

20. An electromagnet comprising a magnetizable core member, a pole piececoacting with said core member and divided into components of differentwidths for dividing the magnetic field, and a plurality of armatures ofdifferent widths coacting respectiv'ely with said ole piece componentsand disposed at di erent distances there from.

21. The combination with a movable contact member, of means forrestraining it in normal position, and electromagnetic means for causiactuation of said restraining means un er different electricalconditions comprising a magnetizable core member, a

10 piece for said core member divided into com onents for dividing themagnetic field, an a plurality'of armatures for actuatingsaidrestraining means cooperatively related respectively with said polepiece components. I

22. i The combination with a movable contact member, of means forrestraining it in normal position, and electromagnetic means for causingactuation of said restraining means under different electricalconditions comprising a magnetizable core member, a pole piece for saidcore member divided into com onents for dividing the magnetic field, ana plurality of armatures for actuating said restraining meanscooperatively related respectively with said pole piece components andspaced at different dis: tances therefrom.

'23; The combination with a movable contact member, of means forrestraining it in normal position, and electromagnetic means into comonents for dividing the magnetic.

field, a p urality of armatures for actuating said restraining meanscooperatively related respectively with said pole piece components, oneof said armatures adaptedvto be freely attracted upon occurrence ofpredetermined overload, and a start-delaying device controlling anotherof said armatures to cause delayed attraction thereof upon persistenceof a lesser overload.

24. Automatic switching apparatus comprising movable contact structure,means for restraining said structure in normal position,electro-magnetic means, and a plurality of armatures, each hingedsubstantially at an end thereof, and arranged magnetically in parallelin the field of said electro-magnetic means, said armatures selectivelyattracted u on occurrence of different predetermine circuit conditionsto actuate said restraining means substantially at the end of movementof the selected armature.

25. Automatic switching apparatus comprising movable cont-act structure,means for restraining said structure in normal position, anelectro-magnetic device, a plurality of armatures arranged magneticallyin parallel in the field of said device, each armature pivotedsubstantially at an end thereof for independent movement by said devicemechanically to actuate said restraining means, and means delayingactuation of said restraining means by one of said armatures until anabnormal circuit condition shall have persisted for a substantialperiod. I v

26. Automatic switching apparatus comprising movable contact structure,means for restraining said structure in normal position, an overloadcoil, pole structure therefor, a plurality of armatures ma netieally inparallel in the field of said coi each of 'said armatures pivoted at oneend and adapted to engage said pole structure at the other end foractuating said restraining means selectively in response to attainmentof predetermined magnitudes of current traversing said coil, and asucker element opera-' higher magnetic susceptibility until an abnormalcircuit condition shall have persisted for a substantial period.

28. Automatic switching apparatus comprising movable contact structure,means for restraining said contact structure in normal position, anoverload coil, pole structure therefor, a pair of armatures ofsubstantially difierent magnetic susceptibility disposed magnetically inparallel in the field of said coil, each armature pivoted substantiallyat an end thereof, means for delaying actuation of said restrainingmeans b the armature of higher magnetic susceptibi ity until an abnormalcircuit condition shall have persisted for a substantial period, andstructure for actuating said restraining means selectively engaged bysaid armatures as the free end of the selectively moved armatureapproaches its final position with respect to said pole structure.

29. Automatic switching apparatus comprising movable contact structure,means for restraining said structure in normal position, an overloadcoil, a pair of armatures of substantially different mass disposedmagnetically in parallel in the field of said coil, and having theircorresponding ends pivoted co-axially, means for delaying actuation ofsaid restraining means by the. armature of greater mass until anoverload of magnitude less than the magnitude to which said otherarmature responds shall have persisted for a substantial riod, andstructure for separately and se ectively actuating said restrainingmeans by said armatures.

30. Automatic switching apparatus comprising movable contact structure,means for retaining said structure in normal an electro-magnetic devicecomprising an overload coil and pole structure, aplurality of armaturesdisposed magnetically in arallel and unsymmetrically in the fiel of saidcoil, each of said armatures pivoted at an end thereof, and trippinmeans for said retaining means actuated armatures as its free endapproaches its final position with respect to said le structure inselective response to pre etermined overload conditions.

31. An electromagnetic device com rising a coil, a pivoted armature, atime-dc ay demeans inc'ludin sition,

y each of said.

sitely knuckle for swingably actuating the second contact-member mto andout of engagement with the first contact-member for res ctively closingand opening the circuit, auditirrent flow responsive means including afirst swingable armature for knuckling the toggle to open the circuit onshort circuit overloads, and a second swingable armature adapted incooperation with the first armature for knuckling the toggle to open thecircuiton simple overloads.

33. An electric circuit interrupting apparatus comprising, incombination, a first contact-member, a second contact-member, togglemeans for actuating'the second contactmember into and out of engagementwith the first contact-member for respectively closing and o ning thecircuit, and tripping means for t e toggle including a pair of coorating armatures, one armature being call rated for actuation on shortcircuit overloads, and the other armature being calibrated to assist theactuation of the first armature on simple overloads.

34. An electric circuit interrupting app;

ratus comprising, in combinatlon, a

contact-member, a second contact-member,

means for actuating the second contact-member into and out of engagementwith the first contact-member for ctively closing and opening thecircuit, an means for actuating the first means to open the circuit,said last a pair of armatures respectivel actua 16 at maximum and lesservalues 0 I current flow and adapted to coact for opening the circuit atless than maximum current flow. f

35. Automatic switching apparatus comprising movable contact structure,electromagnetic means, and a plurality of armatures, each hingedsubstantially at an end thereof and arranged-ma etically in parallel inthe field of sai electro-ma etic means,- said armatures being selectivey attracted upon occurrence of different 'predetermined circuitconditions to actuate said -r WILLIAMMSCOTT.

vice associated therewith,v a second pivoted means including a toggleadapted to oppothe relative positions of said CERTIFICATE OF CORRECTION.I

- Patent No. 1,914,582. I I June 20, 1933.

' WILLIAM M. sport.

It is hereby certified that errorappea're in the printed epecificationof the 1 above numbered patent requiring correction as follows: Page 6,line 117, .for

"suckers,' read suckenSp-andthat the said Lettera Patent should bereadwlth this correction thereinthat the came may conform to the recordof the ca ae in the Patent Office) g I Signed and sealed this 23rd dayof January, A. D. 1934.

I IIo'pkine ($ea l) I Actjng Commi aioner of Patente-

